The present disclosure relates to a fixing device that fixes toner images on a sheet and an image forming apparatus applied with the fixing device.
The fixing device of the image forming apparatus includes a fixing nip portion formed by a fixing roller and a pressurizing roller being brought into press-contact with each other. When the sheet passes through the fixing nip portion, the sheet is pressurized and heated, whereby the toner images on the sheet are fixed on the sheet. Since the sheet is heated when passing through the fixing nip portion, the sheet sometimes adheres to the circumferential surface of the fixing roller. In this case, the sheet winds around the fixing roller after passing through the fixing nip portion.
In order to prevent such winding, a separating member for separating the sheet, which starts to wind around the fixing roller, from the fixing roller is arranged in a position close to the fixing roller on a rotating direction downstream side of the fixing roller. The separating member includes a tabular member extending in the axial direction of the fixing roller. When the distal end of the tabular member and the fixing roller circumferential surface are always in contact with each other, there is a concern that the fixing roller circumferential surface is damaged. When the toner on the sheet is fixed in a state in which the fixing roller circumferential surface is damaged, traces of damage sometimes remain on the toner images. Therefore, a gap having a predetermined distance is formed between the distal end of the tabular member and the fixing roller circumferential surface. The gap is formed by extending the distal end of the tabular member along the circumferential surface of the fixing roller to set the distal end of the tabular member and the axial direction of the fixing roller in parallel to each other.
If the distance of the gap is too small, paper powder sometimes accumulates in the gap portion. On the other hand, if the distance of the gap is too large, sheet separating performance is deteriorated. Therefore, the distance of the gap needs to be set to an appropriate distance that is neither too large nor too small.
However, depending on a twist of the tabular member or a result of alignment of a positional relation between the tabular member and the fixing roller, the distal end of the tabular member cannot be held in parallel to the axial direction of the fixing roller. In this case, the distance between the distal end of the tabular member and the fixing roller circumferential surface cannot be kept uniform.